Heavy rains have increased water levels in the Cauca, which feeds the Ituango Dam in Antioquia province, the country's largest-ever hydroelectric project. Problems with filling mechanisms and tunnels at the dam have authorities on high alert.

"This is an undesirable situation, a complex situation because in our concept that water hitting the base of the dam could erode and possibly destabilize the infrastructure of the dam," said Jorge Londono, the head of Empresas Publicas de Medellin, the public utility company that owns the dam.

The dam, which has not yet begun power generation, has cost nearly $4 billion to build and is meant to generate 17 percent of Colombia's electricity needs. A total of 4,985 people from down-river areas were moved to shelters away from the flood zone, the Andean country's disaster agency said in a statement.

Some 200,000 people live in the 12 towns and populated areas in Antioquia, Bolivar, Cordoba and Sucre provinces that could eventually be affected by possible flooding, authorities said.

Heavy rains have increased water levels in the Cauca, which feeds the Ituango Dam in Antioquia province, the country's largest-ever hydroelectric project. Problems with filling mechanisms and tunnels at the dam have authorities on high alert.

"This is an undesirable situation, a complex situation because in our concept that water hitting the base of the dam could erode and possibly destabilize the infrastructure of the dam," said Jorge Londono, the head of Empresas Publicas de Medellin, the public utility company that owns the dam.

The dam, which has not yet begun power generation, has cost nearly $4 billion to build and is meant to generate 17 percent of Colombia's electricity needs. A total of 4,985 people from down-river areas were moved to shelters away from the flood zone, the Andean country's disaster agency said in a statement.

Some 200,000 people live in the 12 towns and populated areas in Antioquia, Bolivar, Cordoba and Sucre provinces that could eventually be affected by possible flooding, authorities said.